Field of the Invention
The present invention relates to a directed self-assembly composition for pattern formation, and a pattern-forming method.
Discussion of the Background
Miniaturization of various types of electronic device structures such as semiconductor devices and liquid crystal devices has been accompanied by demands for miniaturization of patterns in lithography processes. At present, although fine resist patterns having a line width of about 40 nm can be formed using ArF excimer laser light or the like, even finer pattern formation has been demanded.
To meet such demands, a number of pattern-forming methods are proposed which utilize a phase separation structure induced by the so-called directed self-assembly which leads to spontaneous formation of an ordered pattern. As an example, a method for forming a superfine pattern is known which utilizes directed self-assembly of a block copolymer produced by copolymerizing a monomer compound with a certain property and another monomer compound with a different property (see Japanese Unexamined Patent Application, Publication No. 2008-149447, Japanese Unexamined Patent Application (Translation of PCT Application), Publication No. 2002-519728, and Japanese Unexamined Patent Application, Publication No. 2003-218383). According to this method, by annealing a composition containing the block copolymer, polymer structures having the same property can be assembled, to self-consistently form a pattern. Also, a method is disclosed in which a fine pattern is formed by directed self-assembling of a composition containing a plurality of polymers each having a distinct property (U.S. Patent Application Publication No. 2009/0214823; also see, Japanese Unexamined Patent Application, Publication No. 2010-58403).